[移动开发]集成微信登录

1.在微信开放平台添加需要微信登录的app，审核通过后会得到appId和appSecret
2.添加依赖

implementation 'com.tencent.mm.opensdk:wechat-sdk-android-without-mta:+'
implementation 'com.squareup.okhttp3:okhttp:3.4.1'

3.添加权限

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE"/>
<uses-permission android:name="android.permission.READ_PHONE_STATE"/>
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>

4.新建一个wxapi包，并在该包下新建WXEntryActivity，让该类继承IWXAPIEventHandler

public class WXEntryActivity extends AppCompatActivity implements IWXAPIEventHandler {
    private IWXAPI iwxapi;
    private String unionid;
    private String openid;
    private ProgressBar progressBar;
    private WXEntryActivity mContext;
    private ProgressDialog mProgressDialog;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        iwxapi = WXAPIFactory.createWXAPI(this, "你的appid", false);
        iwxapi.handleIntent(getIntent(), this);

    }

    private void createProgressDialog() {
        mContext=this;
        mProgressDialog=new ProgressDialog(mContext);
        mProgressDialog.setProgressStyle(ProgressDialog.STYLE_SPINNER);//转盘
        mProgressDialog.setCancelable(false);
        mProgressDialog.setCanceledOnTouchOutside(false);
        mProgressDialog.setTitle("提示");
        mProgressDialog.setMessage("登录中，请稍后");
        mProgressDialog.show();
    }

    @Override
    public void onReq(BaseReq baseReq) {

    }

    //请求回调结果处理
    @Override
    public void onResp(BaseResp baseResp) {
        //登录回调
        switch (baseResp.errCode) {
            case BaseResp.ErrCode.ERR_OK:
                String code = ((SendAuth.Resp) baseResp).code;
                getAccessToken(code);
                Toast.makeText(mContext, "登录成功", Toast.LENGTH_SHORT).show();
                break;
            case BaseResp.ErrCode.ERR_AUTH_DENIED://用户拒绝授权
            	Toast.makeText(mContext, "用户拒绝授权", Toast.LENGTH_SHORT).show();
                finish();
                break;
            case BaseResp.ErrCode.ERR_USER_CANCEL://用户取消
            	Toast.makeText(mContext, "用户取消", Toast.LENGTH_SHORT).show();
                finish();
                break；
        }
    }

    private void getAccessToken(String code) {
        createProgressDialog();
        //获取授权
        StringBuffer loginUrl = new StringBuffer();
        loginUrl.append("https://api.weixin.qq.com/sns/oauth2/access_token")
                .append("?appid=")
                .append("你的appid")
                .append("&secret=")
                .append("你的secret")
                .append("&code=")
                .append(code)
                .append("&grant_type=authorization_code");
                
        Log.d("凉城", loginUrl.toString());
        
        OkHttpClient okHttpClient = new OkHttpClient();
        final Request request = new Request.Builder()
                .url(loginUrl.toString())
                .get()//默认就是GET请求，可以不写
                .build();
        Call call = okHttpClient.newCall(request);
        call.enqueue(new Callback() {
            @Override
            public void onFailure(Call call, IOException e) {
                Log.d("凉城", "onFailure: ");
                mProgressDialog.dismiss();
            }

            @Override
            public void onResponse(Call call, Response response) throws IOException {
                String responseInfo= response.body().string();
                Log.d("凉城", "onResponse: " +responseInfo);

                String access = null;
                String openId = null;
                try {
                    JSONObject jsonObject = new JSONObject(responseInfo);
                    access = jsonObject.getString("access_token");
                    openId = jsonObject.getString("openid");
                } catch (JSONException e) {
                    e.printStackTrace();
                }
                getUserInfo(access, openId);
            }
        });
    }

    private void getUserInfo(String access, String openid) {
        String getUserInfoUrl = "https://api.weixin.qq.com/sns/userinfo?access_token=" + access + "&openid=" + openid;

        OkHttpClient okHttpClient = new OkHttpClient();
        final Request request = new Request.Builder()
                .url(getUserInfoUrl)
                .get()//默认就是GET请求，可以不写
                .build();
        Call call = okHttpClient.newCall(request);
        call.enqueue(new Callback() {
            @Override
            public void onFailure(Call call, IOException e) {
                Log.d("凉城424", "onFailure: ");
                mProgressDialog.dismiss();
            }

            @Override
            public void onResponse(Call call, Response response) throws IOException {
                String responseInfo= response.body().string();
                Log.d("凉城424", "onResponse: " + responseInfo);
                SharedPreferences.Editor editor= getSharedPreferences("userInfo", MODE_PRIVATE).edit();
                editor.putString("responseInfo", responseInfo);
                editor.commit();
                finish();
                mProgressDialog.dismiss();
            }
        });
    }
}

5.登录LoginActivity

final IWXAPI api = WXAPIFactory.createWXAPI(this, APP_ID, false);
api.registerApp(APP_ID);

wechat.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View pView) {
                if (!api.isWXAppInstalled()) {
                    Toast.makeText(LoginActivity.this, "您的设备未安装微信客户端", Toast.LENGTH_SHORT).show();
                } else {
                    final SendAuth.Req req = new SendAuth.Req();
                    req.scope = "snsapi_userinfo";
                    req.state = "wechat_sdk_demo_test";
                    api.sendReq(req);
                }
            }
        });

参考：https://blog.csdn.net/u014078990/article/details/83752223